Multiply siftproof bag



Feb. 16, 1943. G. W. POPPE 2,311,248

MULTI-FLY SIFT-PROOF" B-AG Fiied July 11, 1941 FIG. Fm. 2.

INVENTOR GEORGE W. POPPE ATTORN EY Patented Feb. 1 6, v i943 UNITED STATES A'-PAI'IEINT- OFFICE MULTIPLYv .SIFTFROOF BAG George W. f'Poppe, Brooklyn, N. Y., assignorto Equitable Paper BagCc. Inc., Long Island City, N. Y., a corporation ofNew York Application July 11,1941, Serial No. 401,947

I'Claim. (Cl. 229-59)V This invention relates to a multi-ply bag and more particularly to the closure of such a bag.

The type of closure forming the subject matter of the present invention is adapted to thel socalled satchel bottomed bag or the so-called selfopening bag having bellows folds. In making bags of either type a bag tube section is usually provided with a pair of parallel slits extending from the bottom edge of such a section and when the closure is to be made at the top of the bag the parallel slits extend from the top edge of a bag tube section. The end or ends to be closed,l are then opened up and folded to form the closure.

In a multi-ply bag of either the satchel bottomed or self-opening type there isV a possibility of leakage through the closure, especially the bottom closure, when the material forming the i contents of the bag is veryfine.

An object of the present invention is to produce a multi-ply bag which may readily be made on a bag machine and in which the sift-prooi! qualities are greatly enhanced.

A feature of the invention relates to the manner of slitting the different plies of a bag tube section whereby when one end of a section lis opened up and folded, a portion of the folds of an inner ply act to seal the ends of the slits in an outer ply.

'Ihe present type of bag is an improvement on the type shown in the patent to Taggart No. 1,960,929, May 29, 1934. The bag disclosed ln said Taggart patent is apparently limited to one in which the closures, or one of them is adapted to a bag of the satchel bottomed type. 'Ihe closure disclosed herein is adapted either to a bag of the Satchel-bottomed type or so-calledpselfopening type.

Further features and advantages will become apparent from the following description and claim when taken in connection with the accompanying drawing in which:

Fig. 1 is a plan view of one end of a bag tube section which may constitute the outer ply of Aa multi-ply bag, showing the manner of slitting such outer ply;

Fig. 2 is a similar view of an inner ply showing the manner of slitting such ply;

Fig. 3 is a view similar to Figs. 1 and 2 but on an enlarged scale, after the inner ply has jbeen nested within the outer ply. a portion of the slits of the inner ply being indicated in dotted lines;

Fig. 4 is a view on the scale of Fig. `3 of the end view of a bag tube section slit as shown in Fig. 3, but opened up to form a. closure for one end of the bag; and,

of the naps vfolded down and pasted.

v.llteferring to the drawing an outer ply of a Multi-ply lbag tube section is shown in Fig. 1 and is provided at its lower edge with parallel slits I and 2.

The inner ply shown in Fig. 2 is provided with slits `3 and 4 which are parallel for a portion of their length but are also provided with diagonal portions 5 and 6, which diagonal portions extend towards the longitudinal axis of a bag tube section.

when the innerply is nested within the outer ply, kthe slits appear as indicated in Fig. 3. In

this figure a score line a--a is shown as extending transversely ofthe bag section. Lines af-b, a--b indicatelines along which the Ibottom is folded, the latter lines being atan angle of 45 to the longitudinal axis of the bag section.

Referring to Fig. 3, it will be noted that the slits I and 2 and the slits 3 and 4 are superimposed, but the slits 5 and 6 extend at an angle -to the slits '3 and4.

Due to this manner of slitting diagonal folded portions of the inner ply extend beyond the ends 8 of the slits I and! of the outer ply as indi-` cated in Fig. 4. It results from this, that the extended portions of the inner ply act greatly to augment the sift-proof properties of the closure when thefiaps constituting such closure are folded along the fold linesc-c and df-d Fig. 4. In order to secure the bottom of the bag, paste .is `applied in zones between the lines :r-- and 1lll In Fig. 5 the upper flap l0 has been folded along the line c-c and pasted down.

In order to complete the bag, the lower flap l2 is folded up along the line d -d and-likewise pasted. y

In the drawing, the closure has been illustrated in connection with a satchel bottomed bag wherein when the bottom is opened up it forms what is commonly called a diamond fold. This type of bag has been illustrated merely because it is a somewhat simpler form to show.

It is obvious that the type of slitting herein disoily., l

lines a--b, a--b is shown as approximately aright angle, but this angle may be varied.

What I claim is:

A multi-ply bag having a square folded end closure and having an inner and an outer ply, both of which plies are slit to form the bottom fold, an outer ply having spaced parallel longitudinal slits extending inwardly from the bottom edge in the unfolded condition of the bag and terminating at the respective diagonal fold lines, 10 

